ESSENTIALS OF DIAGNOSIS
Evaluation of chronic kidney disease (CKD) includes a thorough medical history, physical exam, and specific laboratory measures.
Symptoms related to CKD may not occur until disease is advanced and include sleep disturbance, decreased attentiveness, nausea, vomiting, weight change, dyspnea, lower extremity edema, fatigue, muscle cramps, peripheral neuropathy, and pruritus.
Reduced estimated glomerular filtration rate (eGFR) (<60 mL/min/1.73 m2) should be interpreted in the context of the medical history and other lab abnormalities (eg, history of diabetic retinopathy, rate of eGFR decline, presence of elevated albumin-to-creatinine ratio) before a diagnosis of CKD is made.
CKD is defined as the presence of reduced glomerular filtration rate (GFR) or evidence of kidney damage for at least 3 months. The prevalence of CKD is highest among older adults. The vast majority of older adults with CKD will die without progressing to end-stage renal disease (ESRD); however, even mild to moderate CKD is associated with functional decline, cognitive impairment, frailty, and multimorbidity.
The Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guidelines were established to direct the evaluation and management of patients with CKD; however, because of the substantial heterogeneity in life expectancy, functional status, and health priorities among older adults with CKD, an individualized, patient-centered approach is appropriate. Among older adults with advanced CKD, a shared decision-making approach should be used to facilitate decisions about dialysis. Geriatric assessment may be helpful to identify older adults who are vulnerable to functional decline and poor outcomes after initiation of dialysis. Palliative and supportive care should be offered to those who experience a high symptom burden regardless of disease stage and dialysis decision.
DIAGNOSIS AND STAGING
The KDIGO Clinical Practice Guidelines provide standardized terminology for the evaluation and stratification of CKD. Based on these guidelines, CKD is defined as abnormalities of kidney structure or function for at least 3 months with implications for health. Abnormalities in kidney function include decreased GFR or other markers of kidney damage (albuminuria, urine sediment abnormalities, electrolyte abnormalities due to tubular disorders, and histologic evidence of abnormalities). After diagnosis of CKD is made, the guidelines recommend staging of CKD using the CGA classification, which stands for cause of kidney disease, GFR level, and albuminuria level.
Among older adults, serum creatinine is a poor marker of kidney function. However, because measuring GFR is not clinically feasible, GFR should be determined using estimating equations based on the serum creatinine and other factors affecting creatinine production including age and gender. Although multiple estimating formulas are available, current guidelines recommend the use of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation because it has been validated in large populations. Estimation of GFR assumes a stable serum creatinine, and therefore, estimated GFR (eGFR) may not be accurate among patients with acute kidney injury (AKI). Cystatin C ...